| 摘要 |
<p>PURPOSE:To effectively utilize the residue of blast furnace dust as sintering raw material by adjusting a slurry of the dust to a weakly alkaline pH range; separating the adjusted slurry into flows of high and low Zn contents; dehydrating the low Zn slurry; and acidifying the resulting cake to extraction-separate Zn. CONSTITUTION:Blast furnace gas washing waste water 1 is adjusted to pH 7-8 with NaOH in pretreatment vessel 2 to deposit dissolved Zn ions. This suspension is fed to settling concn. vessel 3, and the resulting conc. slurry is introduced into wet cyclone 6 through concn. regulation vessel 5 and separated into fine grain overflow 12 of high Zn content and coarse grain underflow 7 of low Zn content. Underflow 7 is fed to dissolution vessel 8, where it is adjusted to pH 4-6 with sulfuric acid, hydrochloric acid or the like to dissolve residual Zn, and underflow 7 is dehydrated with dehydrator 9 to recover extraction residue B1 of low Zn content as sintering raw material. Filtrate 10 is fed to neutralization vessel 11 and adjusted to pH 7-8 to deposit Zn. This slurry is joined with overflow 12 and concn.-dehydrated to recover a Zn-contg. cake.</p> |
